What are the key cultivation techniques for upland rice?

Upland rice is usually cultivated directly in dry land, and is especially suited to low-lying fields. It never requires a water layer throughout its life, relying entirely on natural rainfall or, when drought reaches a certain level, supplemented with a moderate amount of irrigation. Its cultivation and management methods are similar to those of @#@245@#@.

Key points of upland rice cultivation: first, ensure a full stand from a single sowing; second, control weeds in the field; third, all cultivation technical measures must be applied as a complete set.

1. Variety selection. To obtain relatively high yields from upland rice, varieties suited to dry-land cultivation must be selected. The requirements are: (1) the growth period should be moderate; the number of growth days is usually required to be 10-15 days shorter than that of the main locally planted rice varieties; (2) strong seedling soil-penetrating ability, to facilitate rapid emergence and uniform growth; (3) strong drought tolerance, able to grow normally under relatively dry conditions; (4) strong disease resistance, especially resistance to rice blast and narrow brown leaf spot; (5) good yield performance and excellent grain quality. At present, the main upland rice varieties suited to cultivation in Liaoning include Danjing No. 8, Danhan rice No. 1, Hannuo No. 3, and others.

2. Land selection and preparation. Choose low-lying, easily waterlogged land, mountain-intermontane seepage fields, or dry fields or paddy fields with certain irrigation conditions, good water and fertilizer retention, moderately soft soil, and a pH value below 7.5. The quality of land preparation must meet high standards and strict requirements, achieving level ground, fine soil, no visible or hidden clods, and no stubble. Land preparation is best done by autumn plowing (or harrowing) followed by spring rotary tillage. Plots converted from paddy fields to upland rice must be autumn-plowed and harrowed the previous year to prevent large clods at sowing.

3. Timely sowing. To ensure a full stand from a single sowing, select the seeds before sowing, then coat them with a seed coating agent or dress them with methyl isofenphos to prevent damage from underground pests. The sowing time is the same as that of local corn. The sowing rate is 7.5 kg per mu. The sowing method generally uses flat planting with drilling; the row spacing is 30 cm; sow after opening furrows; the furrow depth is 5 cm; the sowing width is 6 cm; and the soil cover thickness is 2 cm. At sowing and after covering with soil, press (tread) firmly. In areas with the conditions, mechanized sequential operations can be carried out.

4. Heavy application of base fertilizer. For growing upland rice, the principle of applying heavy base fertilizer and supplementary topdressing must be mastered. The base fertilizer is generally broadcast as farmyard manure at 2000 kg per mu; after opening furrows, apply a nitrogen-phosphorus-potassium compound fertilizer at 25-30 kg per mu, long-acting ammonium bicarbonate at 30 kg per mu (or urea at 15 kg per mu), and multi-element micronutrient fertilizer at 2 kg per mu. When fertilizer is applied in a concentrated way, the seeds and chemical fertilizer should not be in direct contact and should be separated by soil. In areas with the conditions, whole-layer fertilization can be carried out in combination with rotary tillage. Topdressing depends on the situation; at the tillering stage, apply urea at 7.5-10 kg per mu as appropriate according to growth. For plots that mature relatively late, after full heading, spray potassium dihydrogen phosphate once every 7 days at a rate of 0.2 kg per mu (mixed with 30 kg of water), generally spraying 2 times. For plots that lose fertilizer later, add urea at 1 kg per mu when spraying potassium dihydrogen phosphate.

5. Water management. Apart from using natural rainfall and groundwater in low-lying land, irrigation is generally not needed. In cases of severe drought, supplementary irrigation should be applied manually; the number of irrigations and the amount of water depend on the soil moisture content and the water demand of the upland rice. Except for irrigation of the subsoil moisture before sowing when the soil is dry, generally no irrigation is applied at the seedling stage. After tillering, when the rice plants suffer drought and their leaves roll or wilt, water should be replenished promptly. At the panicle differentiation stage, heading stage, and grain-filling stage, the rice plants have a high water demand and are sensitive to water; this is also an important period determining yield and grain quality. Generally, irrigating 2-3 times during the peak water-demand period of upland rice growth can increase yield by 20-30% and reduce the chalkiness rate.

6. Weed control. The key to the success or failure of upland rice production is weed control in the field. Choose different herbicide formulations according to the weed species and density; generally apply chemicals 2 times. The first is chemical soil sealing, that is, after sowing and before emergence (generally about 7 days after sowing), use butachlor at 0.3 kg per mu and oxadiazon at 0.3 kg per mu plus MCPA at 50 g per mu, mixed with 75 kg of water for spraying (when the soil is dry, the amount of water must be increased; this is an important link determining the effect of chemical sealing and should be highly valued). To improve the effect of chemical sealing, after sowing and before spraying, the surface soil clods must be crushed with a roller to facilitate the formation of the chemical film. The second is treatment of weed stems and leaves; after emergence, when barnyardgrass has 2 leaves, choose a sunny day after the dew has dried and use butachlor at 0.2 kg per mu and quinclorac at 25 g per mu, or use butachlor at 0.2 kg per mu plus propanil at 1.5 kg per mu, mixed with 50 kg of water for spraying (for plots with a low weed density over the years, the second chemical application may also be omitted). When necessary, supplement with manual weeding.

7. Pest and disease control. Coat seeds with a seed coating agent or dress them with methyl isofenphos to control underground pests (special attention should be paid to controlling underground pests in low-lying land). After emergence, if there is damage by mole crickets, use trichlorfon at 0.25 kg per mu plus 20 kg of fine moist soil, mix evenly, and broadcast on the soil surface. About 3 days before the rice panicle breaks through the sheath, use DT fungicide (also known as copper succinate, copper fungicide) at 0.1 kg per mu mixed with 40 kg of water, or from 5 days before the rice panicle breaks through the sheath to the heading stage, use 12% Quwen Junjue at 50 g per mu mixed with 40 kg of water for spraying, to control rice false smut. Other pests and diseases are controlled in the same way as for rice.